If she's growling? Then she's probably going broody! She should be fluffing her feathers out at other chickens around her too. Would this be her first time to set and raise babies?
I've had hens that would scream at me when I'd reach into their cages. When I reached underneath them they'd growl at me.
My hen's that got the yeast infection was constantly drinking water. Wouldn't eat either. Have you tried wetting some crumbles/chick starter to see if she'd eat that? Set it in the nest with her.
If she's going into set mode? She won't leave the nest except to potty, grab a bite to eat, drink and then will go right back to the nest. I always kept the food, water in the cage with the setting hen. I took them out twice a day to potty. I had several hens that would come peck my pants legs when they were ready to go back inside!
TC